The present invention relates to an automobile room lamp system and particularly to an automobile room lamp system mountable to a roof portion between the driver's seat and the front passenger's seat in an automobile and serving as a preferable illumination light for studying a map.
The invention also aims at improving the illumination effect in the whole automobile room.
Conventionally, incandescent light bulbs have been used for interior illumination of the vehicle, which however are being replaced by light emitting diodes (LEDs).
In the automobile room lamp system equipped with conventional light emitting diodes, for example, a 12-volt battery, a light emitting diode (LED), a limited current resistor and a door switch are connected in series, in which the electric resistance of said limited current resistor is set at a value such that a current of a predetermined value flows through the light emitting diode. (See Official Gazette of Japanese Patent No. 3660267)
The conventional automobile room lamp system has a problem that the illumination performance is very poor as a result of power loss due to voltage drop because the light emitting diode (LED) is lighted by the current flowing from the battery through the limited current resistor.
Further, the limited diffusion of the illumination light due to its high directivity merely serves for spotlighting.
In other words, while such illumination is satisfactory for consulting a map, it fails to meet the user's needs for the effect of the automobile room lamp system to make the whole interior of the automobile brighter.